The present invention relates to the field of semiconductor sensors, and in particular to a semiconductor sensor device that includes a carrier chip comprising a sensor structure with an active sensor surface, wherein a flowable material is applied to and bounds the active sensor surface region of the carrier chip, and the flowable material is then solidified.
As known, for manufacturing a semiconductor sensor device, a block is first placed on the active sensor surface before flowable material is applied to the sensor chip. The outer contour of the block is matched to the outer contour of the sensor surface, so that, when the block is in its operational position, it covers only the sensor surface, while the regions surrounding the sensor surface are not covered by the block. The form of the surface structure of the block area that contacts the active sensor surface is matched to that of the active sensor surface, so the block seated on the sensor surface seals it against the flowable material. This material is then applied to the surface of the sensor chip in the area surrounding the block, and is then solidified. For example, the flowable material can be a plastic compound that cures or rigidifies after being applied to the sensor chip. The active sensor surface is then freely accessible for contact with a medium being investigated, while the surface regions laterally surrounding the active sensor surface are sealed by the plastic compound.
However, this method has a disadvantage that the block must be positioned on the sensor surface very precisely, to prevent the flowable material from penetrating between the block and the sensor surface. That is, the block must be precisely positioned to prevent the sensor surface from being covered with the flowable material. A further disadvantage is that the carrier chip is damaged when the block is placed on the sensor surface, and thus the device is rendered useless or at least defective. Another disadvantage of this method is that the production of the block and especially of the surface structure of that component which is complementary to the surface structure of the sensor surface when the block is in its operating position is still comparatively expensive. Finally, this known method is also unsuited for automation, and thus the economical mass production of sensors.
Therefore, there is a need for a technique of providing a protective covering over the sensor surface, the application of which does not damage the sensor.